Adult:
Physically highly variable, easy to confuse with other Cophixalus
species without a call recording. Base colour ranges from grey to brown with
darker mottling. The side of the head is dark brown, and the upper eyelid
iridescent green. There is a pale area just above the groin, most noticeable
in darker specimens. The belly is pale or pale-spotted, and the male has a
dark throat. The digits are unwebbed and lack
toe discs.

Call: A fast, high-pitched tapping, described as "like a marble on a
tile" (Queensland Museum 2000).

Similar
species: Other Cophixalus species with which it shares its range,
and from which it can most reliably be distinguished by its call. Smaller
size and the absence of toe discs distinguish this species from the
sympatric tapping
nursery frog (C. aenigma). The mountaintop nursery frog (C.
monticola) is closely associated with palms, which it appears to use as
retreat sites, and occurs only above 1,000 m. Smaller size and the lack of
webbing between the digits distinguishes this species from other small
terrestrial frogs.

During the day, frogs rest under logs and rocks; when disturbed they will
often remain motionless, relying on their
cryptic colouration to
evade detection.

Reproductive behaviour: Courtship in this species has never been observed,
though is presumed to be similar to that recorded for the ornate nursery
frog. In one instance, a male attendant has been found guarding a clutch of
hatchlings. In related species, males guarding clutches may
call and may attend several clutches simultaneously.

Breeding biology: In common with other members of the genus, C.
hosmeri lays small clutches of terrestrial eggs which are guarded by an
adult attendant and which undergo
direct development.
A single clutch has been recorded for this species, which when discovered
contained seven hatchlings.

Hosmer's frog is listed as nationally Rare in Australia. Its Red List
rating reflects the fact that this species is found in fewer than five
locations; as a high-altitude species, it may also be susceptible to the
impacts of climate change. However, within its range it may be among the
most commonly encountered frog species.